Hay conditioners generally include a pair of rollers mounted in co-extensive parallel relationship for rotation about respective axes with the crop arranged to pass between the rollers in a conditioning action.
Each of the rollers carries a plurality of longitudinally extending angularly spaced flutes which project outwardly from the surface of the roller. The rollers are spaced by a distance such that the flutes intermesh generally without contact between the rollers. The intermeshing of the flutes causes the crop material to be bent as it passes between the rollers causing a cracking of the waxy surface of the crop stem.
It is necessary in such rollers to allow one of the rollers, generally the top roller, to move in a direction to increase the spacing between the axes of the rollers to accommodate different amounts of crop material passing between the rollers and to accommodate obstacles such as stones and sticks which pass through without damage to the rollers. Generally this movement is provided by suspending each end of the top roller on a spring biasing system which allows each end independently to rise and lower in a floating action.
In view of the fact that the rollers carry intermeshing flutes, it is essential to ensure that the rollers are driven in synchronism at all times including accommodating the lifting movement while synchronism is maintained.
A number of previous designs have been proposed and manufactured to provide the drive from the first roller to the second roller to maintain the necessary synchronism. One arrangement includes a gear box having an input attached to the bottom roller and an output shaft attached to the top roller. The output shaft includes universal joints which allows the output shaft to accommodate the up and down movement of the top roller shaft. The gear box arrangement is expensive and is of relatively wide width.
An alternative arrangement includes a double chain drive system. In this system, a drive sprocket on the end of the bottom roller and two idler sprockets are located in a common plane at right angle to the axis of the bottom roller at the apexes of a triangle. A chain wrapped around these three sprockets engages a fourth sprocket driven by the chain between the drive sprocket and one of the idler sprockets. A second chain communicates drive from a fifth sprocket coaxial with and co-rotatable with the fourth sprocket to a driven sprocket on the end of the top roller. The top roller is then positioned within the apexes defining the triangle and can pivot relative to the axis of the fourth and fifth sprocket. This arrangement is highly complex involving a high number of idler sprockets thus increasing cost and increasing chain wear. The double chain arrangement also significantly increases the width of the device since it must accommodate the two chains side by side.
A yet further arrangement is shown in U.S. Pat. No. 5,435,239 (Talbot) issued Jul. 25, 1995 and assigned to the present assignees. This shows a particular chain driving system which communicates drive from the bottom roller to the top roller while ensuring the proper synchronism despite changes in spacing between the rollers, while acting to minimize the size and complexity of the drive system.
However there remains a requirement to yet further increase the length of the rollers to maximize crop throughput and to minimize the amount of crop per unit length to obtain the best conditioning action on the crop. At the same time, the amount of space available is limited by the geometry of the supporting machine, and in some designs the conditioner is located between two spaced support legs of the frame of the machine which are set at a distance which cannot readily be changed. The only way therefore to increase the length of the rollers is to reduce the width of the drive system which must be accommodated at the end of the rollers between the legs. Attempts, such as that in the above Talbot patent have been made therefore for many years to minimize the complexity of the drive and therefore its dimension.
At the same time, the shape and arrangement of the flutes must be selected to ensure effective conditioning.
Prior U.S. Pat. No. 6,220,007 (Doerr) assigned to Vermeer, U.S. Pat. No. 5,056,302 issued Oct. 15, 1991 (Rosenbalm) assigned to Deere and U.S. Pat. No. 5,357,737 issued October 25, 1994 (Ermacora) assigned to Kuhn all provide a design using meshing gears which connect from a gear on the driven bottom roller through idler gears to a driven gear on the top roller. In all these patents the top roller is mounted for movement in an arc about a pivot point. The gear arrangement is designed to minimize or reduce changes in angular timing between the rollers as they rotate while the distance between them is varying.
In Canadian Application 2,406,419 filed Oct. 4, 2002 and published in April 2004 by the present Assignees is disclosed an arrangement in which timing is communicated between the rollers by a resilient rubber star wheel on one of the rollers which meshes with a rigid gear wheel on the other. This arrangement has not proven to be successful.